Patent GB-200873-A (GB)
Title: New methods of dyeing acetyl-silk and union or mixed fabrics containing it
IPC: D06P1/12
Filed: 1922-03-18
Abstract: N-methyl-o -sulphonic acids of azo dyes suitable for dyeing acetyl silk are obtained by treating a primary or secondary amidoazo compound with formaldehyde-bisulphite, or by coupling an unsulphonated diazo compound with a methyl-o -sulphonic acid derived from a primary or secondary amine of the benzene or naphthalene series, or by sulphide reduction of a p-nitroamidoazo-methyl-o -sulphonic acid as described in Specification 197,809, or by coupling an amine or phenol with a diazotized diamine, one amino group of which has been converted into its methyl-o -sulphonic acid derivative.  Similar products derived from aldehydes other than formaldehydes may be obtained. Dyestuffs are described (1) from diazo compounds and the reaction products from formaldehyde bisulphite and methyl- or ethyl-aniline or methyl-o-toluidine; as diazo component are mentioned m- and p-nitroaniline, and 2 : 4-dinitroaniline; (2) by sulphide reduction of the dyes from p-nitrodiazobenzene and the reaction products from formaldehyde-bisulphite and methyl- or ethylaniline or methyl-o-toluidine; (3) from p unsym-dimethyl-di-p-amido-azobenzene and formaldehyde bisulphite; (4) from amidoazobenzene, benzaldehyde, and bisulphite; (5) from p-nitrodiazobenzene and aniline-o -ethylsulphonic acid, C6H5-NH-CH (CH3), SO3H.ALSO:The dyeing or printing of acetyl silk or fabrics containing it is effected from neutral or faintly acid or alkaline baths by means of the N-alkyl-o -sulphonic acids derived from aminoazo compounds not containing sulphonic groups attached to the benzene or naphthalene nuclei; they may be prepared by treating the aminoazo compound with formaldehyde bisulphite; the N-alkylsulphonic groups split off during the dyeing.  Such of the aforesaid dyestuffs as are derived from primary aminoazo compounds may be diazotized upon the fibre and developed with the usual components; those which are derived from secondary aminoazo compounds and which do not contain a primary amino group or an alkyl-o -sulphonic group attached to a primary amine group are not diazotizable; such compounds may be prepared by coupling unsulphonated diazo compounds with the products of the action of formaldehyde bisulphite upon monomethyl or monoethyl aniline or monomethyl-o-toluidine; diazotizable dyestuffs are obtained for example by sulphide reduction of the dyestuffs from p-nitrodiazobenzene and the N-methyl o -sulphonic acids from methyl- or ethyl-aniline or methyl-o-toluidine as described in Specification 197,809.  The corresponding dyestuffs derived from aldehydes other than formaldehyde may also be employed.  The dyestuffs which contain only one azo-group have little affinity for cotton, linen, &c. so that cotton in mixed fabrics may remain undyed or may be dyed simultaneously by addition of a cotton dyestuff; the colours on the two fibres may be diazotized and developed in various shades depending upon the choice of developer, and, since the diazotized colour on the cotton &c. develops more quickly than that on the acetyl-silk, one developer may be washed off and the acetyl silk developed with another.  For printing, the N-alkyl-o -sulphonic acids are applied in the form of thickened solutions, preferably made slightly acid with an organic acid, dried and steamed; they may be printed in conjunction with basic or cotton dyes and the prints diazotized and developed as in the case of dyeings; discharge effects may be obtained with a discharging agent such as Formosol.  Examples are given of the production of yellow, red, brown, blue, black, &c. shades upon acetyl silk or mixtures thereof with cotton by use of the following dyestuffs:-(1) dyestuff from unsymdimethyl-di-p-amidoazobenzene and sodium bisulphite-formaldehyde; it may be diazotized on the fibre and developed with dimethylaniline, acetoacetic ether, m-amidophenol, m-phenylene diamine, 1 : 7-amidonaphthol, b -naphthylamine, a -naphthylamine ether, phenol, b -naphthol, or b -oxynaphthoic acid; (2) p-nitrobenzene-azo-methylaniline-o -sulphonic acid, or p-nitrobenzene-azoaniline-o -ethylsulphonic acid NO2.C6H4.N2.C6H4. NH.CH(CH3)(SO3H); these may be diazotized and developed with resorcin, acetoacetic ether, b -naphthol, a -naphthol, m-amidophenol, 1 : 7 amidonaphthol, b -naphthylamine, a -naphthylamine ether, or m-phenylene diamine; (3) m-nitrobenzene-azo-dimethylaniline-o -sulphonic acid; (4) 2 : 4-dinitrobenzene-azo-ethylaniline-methyl-o -sulphonic acid; (5) the dyestuff from amidoazobenzene, benzaldehyde and sodium bisulphite; this may be diazotized and developed with dimethylaniline, phenol, resorcin, b -naphthol, or b -oxynaphthoic acid.  In other examples mercerized cotton cloth containing "effect" threads of acetyl silk, or hosiery containing cotton and acetyl silk is dyed with a mixture of the disazo dye from benzidine, H-acid and gamma-acid, and p-nitrobenzene-azomethylaniline-o -sulphonic acid; upon diazotizing and developing with b -naphthol the cotton is dyed dark blue and the silk red, but by developing with 1.7-amidonaphthol the cotton becomes black and the silk dark purple: cotton cloth embroidered with acetyl silk is dyed with a mixture of primuline and the dyestuff (1) above, the whole being dyed yellow; upon diazotizing, developing for one minute with b -naphthol, rinsing, and then developing with a -naphthylamine ether the silk is dyed black and the cotton red.